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neha.yargal

8 years agoPosted 8 years ago. Direct link to neha.yargal's post “how to identify that the ...”

how to identify that the problem is sample problem or population

problem?•

(31 votes)

Jonathon

8 years agoPosted 8 years ago. Direct link to Jonathon's post “Great question! It depen...”

Great question! It depends on why you are calculating the standard deviation. In the case of sampling, you are randomly selecting a set of data points for the purpose of

**estimating**the true values for mean, standard deviation, etc. In the case of a population problem you are collecting data points from 100% of the subjects you wish to study.(53 votes)

tamjrab

8 years agoPosted 8 years ago. Direct link to tamjrab's post “Why standard deviation is...”

Why standard deviation is a better measure of the diversity in age than the mean?

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(9 votes)

Andrea Rizzi

8 years agoPosted 8 years ago. Direct link to Andrea Rizzi's post “I'll try to give you a qu...”

I'll try to give you a quick example that I hope will clarify this. If you picked three people with ages 49, 50, 51, and then other three people with ages 15, 50, 85, you can understand easily that the ages are more "diverse" in the second case. In the first case people are all around 50, while in the second you have a young, a middle-aged, and an old person.

However, in both cases the average is 50! The average cannot pick on this diversity, and in fact it doesn't measure diversity at all, only central tendency. On the other hand, the standard deviation turns out to be 0.8, and 28.6 respectively, and correctly assigns greater "diversity" to the second case. Hope this helps!

(73 votes)

Alfonso Parrado

6 years agoPosted 6 years ago. Direct link to Alfonso Parrado's post “Why do we have to substra...”

Why do we have to substract 1 from the total number of indiduals when we're dealing with a sample instead of a population? I know how to calculate the sample standard deviation, but I want to know the underlying reason why the formula has that tiny variation

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(19 votes)

Pedro IPF

7 years agoPosted 7 years ago. Direct link to Pedro IPF's post “If the sample has about 7...”

If the sample has about 70% or 80% of the population, should I still use the "n-1" rules?? Or i just divided by n?

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(6 votes)

ragetactic27

5 years agoPosted 5 years ago. Direct link to ragetactic27's post “this is why I hate both l...”

this is why I hate both love and hate stats. how can you effectively tell whether you need to use a sample or the whole population? (this seems to the be the most asked question)

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(4 votes)

Saivishnu Tulugu

5 years agoPosted 5 years ago. Direct link to Saivishnu Tulugu's post “You have to look at the h...”

You have to look at the hints in the question. With popn. you will usually see words like all, true, or whole. For sample, words will be like a representative, sample, this group, etc.

(7 votes)

23altfeldelana

4 years agoPosted 4 years ago. Direct link to 23altfeldelana's post “If a problem is giving yo...”

If a problem is giving you all the grades in both classes from the same test, when you compare those, would you use the standard deviation for population or sample?

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(4 votes)

Kailie Krombos

4 years agoPosted 4 years ago. Direct link to Kailie Krombos's post “If you are assessing ALL ...”

If you are assessing ALL of the grades, you will use the population formula to calculate the standard deviation.

A way to remember the difference is that a sample is only a group, a part of a whole. The population is referring to the entire set. So when you are receiving data from the ENTIRE population, you can be confident in using the population formula. If you are only given data from a PART of the group, you know to use the sample formula. I hope this helps!

(4 votes)

Izzah Nabilah

7 years agoPosted 7 years ago. Direct link to Izzah Nabilah's post “Can i know what the diffe...”

Can i know what the difference between the (∑(x-μ)^2)/N formula and [∑x^2-((∑x)^2)/N]N this formula. How can i know which one im suppose to use ?

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(5 votes)

021490

3 years agoPosted 3 years ago. Direct link to 021490's post “How do I find the standar...”

How do I find the standard deviation if I am only given the sample size and the sample mean?

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(4 votes)

RyanYang14

a year agoPosted a year ago. Direct link to RyanYang14's post “I don't think you can sin...”

I don't think you can since there's not enough information given

(2 votes)

Evelyn Lutz

5 years agoPosted 5 years ago. Direct link to Evelyn Lutz's post “is The standard deviation...”

is The standard deviation for a sample is most likely larger than the standard deviation of the population?

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(3 votes)

Bryanna McGlinchey

5 years agoPosted 5 years ago. Direct link to Bryanna McGlinchey's post “For the population standa...”

For the population standard deviation equation, instead of doing mu for the mean, I learned the bar x for the mean is that the same thing basically? If so, then why use mu for population and bar x for sample?

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(3 votes)